Four dead bodies were found in North Sinai on Monday afternoon, bringing the total number of bodies discovered in the area on Monday to seven.
The victims, who all died of gunshot wounds, were found in different parts of Sheikh Zwayed and Rafah.
According to a security source who spoke to Al-Ahram Arabic website, five of the seven men hailed from the Armilat family in Al-Matla village. The two other victims belong to members of the Sawarka clan.
On Saturday, Egyptian police had found two other decapitated bodies in North Sinai's Sheikh Zwayed.
Egypt's most active militant group, Ansar Beit Al-Maqdis, which swore allegiance to the Islamic State last November, had already claimed responsibility for the killing of at least 12 people by decapitation last year, accusing them of collaborating with the Egyptian army or Israeli intelligence.
Security forces have been battling an Islamist militant insurgency in Sinai for over a decade. However, since the ouster of Islamist president Mohamed Morsi, militant attacks have escalated, mainly targeting security forces.
Ansar Beit Al-Maqdis has claimed responsibility for most of the attacks in Sinai since Morsi's overthrow in July 2013.